Field of the Invention
The present invention relates to X-ray generators that generate X-ray radiation and that are applicable to medical equipment, nondestructive inspection apparatuses, and other similar instruments.
Description of the Related Art
There is a need to generate X-rays with stability while suppressing fluctuations in the intensity of outputting the X-rays in an X-ray generator.
One of the major factors in determining the stability in the X-ray generator can be thermal durability of a target that is a source of X-ray radiation.
“X-ray generating efficiency” in a target in an X-ray generator that irradiates the target with electron beams and generates X-rays is on the order of 1%. That is, almost all of the energy input into the target is converted into heat. If “heat dissipation” of heat generated in the target is insufficient, the temperature of the target increases excessively. The excessive heat produces negative effects including melting, evaporating, or thermal stress of the target, and a decrease in the adhesion of the target to its support. Therefore, insufficient or ineffective heat dissipation limits the thermal durability of the target.
One of the publicly known methods for improving the “X-ray generating efficiency” in the target is the use of a transmission-type target. A transmission-type target includes a target layer having a thin film formed of a heavy metal and includes a base allowing X-rays to pass therethrough and supporting the target layer. Japanese Patent Application Publication No. JP 2009-545840 (also published as WO 2008/060671) discloses a transmission-type target of the rotating anode type in which the “X-ray generating efficiency” is equal to or greater than 1.5 times that of a known reflection-type target of the rotating anode type.
The use of diamond in a base that supports a target layer in a transmission-type target is publicly known as a method for facilitating “heat dissipation” from the target to the outside. U.S. Pat. No. 6,850,598 discloses in its specification the use of single crystal diamond or polycrystalline diamond as a transmission substrate that supports a target layer and that allows X-rays to pass therethrough. Diamond has high heat resistance and high thermal conductivity, and also has high X-ray transmittance, and thus it is a suitable material as a supporting base in a transmission-type target.
One publicly known method to obtain stable X-ray output is disposing a connection electrode or wax material between a target layer and an anode member and establishing electrical connection therebetween.
However, for the above-described configuration including the connection electrode, fluctuations in outputting X-rays or discharge may occur. Therefore, there is a need to improve the reliability of the electrical connection between the target layer and the anode member.